Brush chipper assembly with counter-rotating feeder rollers and chipping heads

ABSTRACT

A brush chipper assembly has a housing and a feeder subassembly connected to the housing. The feeder subassembly includes opposed, first and second feeder rollers. When the feeder subassembly is actuated, the first feeder roller is operable to rotate in a first direction and the second feeder roller is operable to rotate in a second direction (opposite to the first direction) so as to draw the brush into the housing. Also provided is, a chipping subassembly substantially contained within the housing behind the feeder subassembly. The chipping subassembly including first and second, opposed chipping heads, each of which carrying cutting teeth for chipping the brush. When the chipping subassembly is actuated, the first chipping head is operable to rotate in a third direction (opposite to the first direction) and the second chipping head is operable to rotate in a fourth direction (opposite to the second direction).

FIELD OF THE INVENTION

The present invention relates generally to brush chipper assemblies, andmore specifically, to a brush chipper assembly with counter-rotatingfeeder rollers and chipping heads.

BACKGROUND OF THE INVENTION

Conventional brush chippers are typically configured with a housingwhich accommodates a single, relatively large, rotatable drum or roller.In such chippers, the drum is mounted for rotation about a horizontalaxis. Carried on the outer surface of the drum is a plurality of cuttingor chipping elements which are designed to make contact with the brushas the drum is rotated, and to reduce the brush to chips. Such chippersoften have a conveyor system consisting of combination of one or moreconveyor belts or feeder rollers. This system serves to transport thebrush being fed into the front of the housing, rearward toward the drum.Commonly, the drum is rotated in a clockwise direction such that thehorizontal component of the force exerted by the cutting elements on thebrush acts in the same rearward direction.

To improve effective chipping action of their brush chippers, some brushchipper manufacturers have increased the size of their drum to exposethe brush to a broader chipping area. These large diameter brushchippers tend to be very powerful and exhibit good chipping abilities,but because of their weight they tend to draw more power thansmaller-sized drums and require a more robust support frame andbearings. Also, based on safety considerations, there may be someconstraints as to the speed at which such drums may be rotated.

In light of the foregoing, it would be advantageous to have a brushchipper assembly that exhibits enhanced chipping action withoutrequiring the use of a relatively, large sized, heavy drum withsignificant energy demands.

SUMMARY OF THE INVENTION

In accordance with one broad aspect of the present invention, there isprovided a brush chipper assembly which has a housing and a feedersubassembly connected to the housing. The feeder subassembly includesopposed, first and second feeder rollers. When the feeder subassembly isactuated, the first feeder roller is operable to rotate in a firstdirection and the second feeder roller is operable to rotate in a seconddirection so as to draw the brush to be chipped into the housing. Thefirst direction of rotation is opposite to the second direction ofrotation. The brush chipper assembly is also provided with a chippingsubassembly substantially contained within the housing behind the feedersubassembly. The chipping subassembly includes first and second, opposedchipping heads and a drive assembly for driving rotation of the firstand second chipping heads. Each chipping head carries a plurality ofcutting teeth for chipping the brush fed into the brush chipperassembly. When the chipping subassembly is actuated, the first chippinghead is operable to rotate in a third direction and the second chippinghead is operable to rotate in a fourth direction. The third direction ofrotation is opposite to the fourth direction of rotation and the firstdirection of rotation. The fourth direction of rotation is opposite tothe second direction of rotation.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the present invention shall be more clearlyunderstood with reference to the following detailed description of theembodiments of the invention taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a front view looking down taken at a brush chipper assemblyaccording to an embodiment of the present invention;

FIG. 2 is a front elevation view of the brush chipper assembly of FIG. 1showing the left and right feeder rollers of the feeder subassembly;

FIG. 3 is a rear elevation view of the brush chipper assembly of FIG. 1with a portion of the housing of the brush chipper assembly removed toreveal details of the left and right chipping heads of the chippingsubassembly;

FIG. 4 is a right side elevation view of the brush chipper assembly ofFIG. 1;

FIG. 5 is a left side elevation view of the brush chipper assembly ofFIG. 1;

FIG. 6A is a top plan view of the brush chipper assembly of FIG. 2showing the left and right feeder rollers of the feeder subassemblyoccupying respective first positions wherein a preset minimum gap existsbetween the left and right feeder rollers;

FIG. 6B is another top plan view similar to that shown in FIG. 6A exceptthat the left and right feeder rollers of the feeder subassembly areshown moving from their respective first positions (depicted in dashedlines) to their respective second positions (depicted in solid lines)wherein a preset maximum gap exists between the left and right feederrollers;

FIG. 7A is another top plan view similar to that shown in FIG. 6A exceptthat the upper linkage mechanism connecting the left feeder roller tothe right feeder roller has been removed to better reveal details of thedrive assembly of the chipping subassembly;

FIG. 7B is a partial perspective view of the brush chipper assemblyillustrated in FIG. 7A showing the drive assembly of the chippingsubassembly;

FIG. 8 is a bottom plan view of the brush chipper assembly of FIG. 2;

FIG. 9A is a cross-sectional view of the brush chipper assembly shown inFIG. 2 taken along line “9A-9A” with the hydraulic motor of the driveassembly omitted for clarity;

FIG. 9B is an enlarged end view of the encircled portion “9B” of thebrush chipper assembly illustrated in FIG. 9A showing a cutting toothassembly of the right chipping head;

FIG. 10 is a schematic cross-sectional view similar to that shown inFIG. 9A showing a tree branch being drawn into the brush chipperassembly by the counter-rotating left and right feeder rollers and beingacted upon by the oppositely counter-rotating left and right chipperrollers to produce wood chips therefrom;

FIG. 11 is an isolated perspective view of the housing of the brushchipper assembly shown in FIG. 1;

FIG. 12A is an isolated side elevation view of the right feeder rollerillustrated in FIG. 4, with a portion of the roller body removed toreveal details of the interior thereof;

FIG. 12B is an isolated cross-sectional view of the bottom bearingsupport and the bottom shaft of the right feeder roller shown in FIG.12A;

FIG. 12C is an exploded view of the bottom bearing support shown in FIG.12B;

FIG. 13A is an isolated side elevation view of the right chipping headillustrated in FIG. 3, with collars, cutting tooth assemblies and aportion of the support body removed to reveal details of the interior ofthe support body, including the arrangement of upper and lower couplingassemblies within the hollow of the support body;

FIG. 13B is an isolated cross-sectional view of the upper couplingassembly of the right chipping head shown in FIG. 13A; and

FIG. 13C is an exploded view of the upper coupling assembly shown inFIG. 13B.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

The description which follows, and the embodiments described therein areprovided by way of illustration of an example, or examples of particularembodiments of principles and aspects of the present invention. Theseexamples are provided for the purposes of explanation and not oflimitation, of those principles of the invention. In the descriptionthat follows, like parts are marked throughout the specification and thedrawings with the same respective reference numerals.

Referring to FIGS. 1 to 5, there is shown a brush chipper assemblygenerally designated with reference numeral 20. The brush chipperassembly 20 is operable to reduce felled trees, tree trimmings, branchesor other like feedstock into wood chips and cutting debris. It is of thetype which may be attached to a frame provided at the end of a hopper, atrailer or the like, or which may be incorporated as part of a combinedchipping and baling machine or other similar machine. The brush chipperassembly 20 includes a housing 22, a feeder subassembly 24 carried infront of the housing 22, and a chipping subassembly 26 substantiallycontained within the housing 22 behind the feeder subassembly 24.

By way of general overview, the feeder subassembly 24 includes opposed,vertically extending, left and right feeder rollers 28 and 30, and upperand lower linkage mechanisms 32 and 34 connected to the feeder rollers28 and 30 and operable to adjust the gap G between the left feederroller 28 and the right feeder roller 30. When counter-rotated (i.e.when each is rotated in a direction opposite to the other), the feederrollers 28 and 30 co-operate with each other to draw rearwardly into thechipping subassembly 26 the felled trees, tree trimmings, branches orthe like which are to be reduced to wood chips. As depicted in FIG. 10,to achieve this result, the left feeder roller 28 is rotatedcounter-clockwise and the right feeder roller 30 is rotated clockwise.

The main components of the chipping subassembly 26 are opposed,vertically extending, left and right chipping heads 36 and 38, and adrive assembly 40 for driving rotation of the left and right chippingheads 36 and 38. The chipping heads carry a plurality of cutting teethfor chipping the feedstock. During actuation of the chipping subassembly26, the left and right chipping heads 36 and 38 are also counter-rotated(i.e. each is rotated in a direction opposite to the other) to reducethe feedstock to wood chips and chipping debris. However, as will beexplained in greater detail below, the rotation of the chipping heads 36and 38 is such that it opposes the advance of the feedstock further intothe housing 22. This occurs because the left chipping head 36 is rotatedclockwise (in a direction opposite to that of the left feeder roller 28)and the right chipping head 38 is rotated counter-clockwise (in adirection opposite to that of the right feeder roller 30), as shown inFIG. 10. The horizontal component of the force generated by the impactof the cutting teeth on the feedstock, acts in a direction opposite tothe direction of the propulsive force of the feeder rollers 36 and 38(i.e. the direction of travel of the branch 810). As a result, a moreeffective chipping action may be achieved.

Turning now to a more detailed discussion of the elements referred toabove and with reference to FIGS. 9 and 11, the housing 22 has a frame42 of welded construction which is made up of several frame elements,namely: top left and right panels 44 and 46, bottom left and rightpanels 48 and 50 disposed opposite the top panels 44 and 46, a leftsidewall member 52 extending between the top left panel 44 and thebottom left panel 48, and a right sidewall member 54 extending betweenthe top right panel 46 and the bottom right panel 50. The top left panel44, the bottom left panel 48 and the left sidewall member 52 arearranged to form a mirror image of the top right panel 46, the bottomright panel 50 and the right sidewall member 54. In like fashion, thetop left and right panels 44 and 46, and the bottom left and rightpanels 48 and 50 are symmetrically arranged about a notional horizontalplane H extending through the frame 42.

As a result of the horizontal and vertical symmetry of the frame 42, thepanels 44, 46, 48 and 50 resemble each other, such that the descriptionof top left panel 44 will generally suffice for the other panels 46, 48and 50. Where necessary, a more specific description of the other panels46, 48 and 50 will be provided. Top left panel 44 is fabricated fromstructural steel and has a top face 56 and a bottom face 58 (visible inFIG. 5). The panel 44 is generally square-shaped with two truncatedcorner portions 62 and 64 trimmed at an angle—one of which (cornerportion 62) significantly so. The corner portion 66 is smoothlyradiused. The shape of the panel 44 is defined by a plurality of edges,namely: a front edge 68 extending between front right and left rightcorner portions 60 and 62; a left side edge 72 extending between thefront left corner portion 62 and the rear left corner portion 66; a rearedge 74 running between the rear left corner portion 66 and the rearright corner portion 64; and a right side edge 78 extending between therear right corner edge 76 and the front right corner portion 60.

Cut into the right side edge 78 at a location closer to corner portion60 than to corner portion 64, is an oblong rebate 80. A correspondingrebate 82 is formed in the top right panel 46 and because of thesymmetry of the frame 42 the rebate 82 is disposed directly opposite tothe rebate 80. The rebate 80 in the top left panel 44 is aligned with acorresponding rebate 84 formed in the bottom left panel 48. The rebates80 and 84 are configured to receive portions of the left chipping head36. Similarly, a rebate 82 in the top right panel 46 is aligned with acorresponding rebate 86 defined in the bottom right panel 50. Therebates 82 and 86 are configured to receive portions of the rightchipping head 38.

The top left panel 44 also has a cylindrical support member 90 thatstands tall from, and is welded to, its top face 56 at a location closerto rear and left side edges 74 and 72 than to the front and right sideedges 68 and 78. The support member 90 carries a short post 92 which isconfigured for engagement with a portion of the upper linkage mechanism32. The short post 92 includes a lower portion 94 and an upper portion96. The lower portion 92 has a slightly larger diameter than the upperportion 96, and has a smooth outer wall 98. The upper portion 94 hasthreading along its outer wall 100.

The other panels 46, 48 and 50 also have similarly formed cylindricalsupport members 110, 112 and 114, respectively, projecting from theirrespective top faces, except that the cylindrical support member 110stands taller than the support members 90, 112 and 114. As will beexplained in greater detail below, the cylindrical support members 90and 110 provide points of attachment for the upper linkage mechanism 32while the cylindrical support members 112 and 114 support provide pointsof attachment for the lower linkage mechanism 34.

As best shown in FIGS. 4 and 5, the front edge 68 of the top left panel44 is carried higher than the rear edge 74 thereof; the portion of theleft top panel 44 adjacent the front edge 68 being upturned to form atop left deflector 120 for deflecting away chipping debris. The righttop panel 46 is similarly formed with a top right deflector 122. In thecase of the bottom left and right panels 48 and 50, the portion of thesepanels that are adjacent their respective front edges 124 and 126 areturned downwardly to form bottom left and right deflectors 128 and 130.

Adjacent the front left corner edge 70 of the top left panel 44, thereis defined a relatively large circular aperture 132 sized to receive aportion of the drive assembly 40.

Plates 134 and 136 fastened to the top left and right panels 44 and 46serve to connect the left and right sides of the frame 42. In a likearrangement, plates 138 and 140 are fastened to the bottom left andright panels 48 and 50 (see FIGS. 4 and 5).

Each of the top and bottom left panels 44 and 48 have a set of fourapertures 142, 144, respectively, defined adjacent their respective leftrear corner portions. The apertures 142 in panel 44 are aligned with theapertures 144 in panel 48. Both sets of apertures 142 and 144 areconfigured to receive fasteners for attaching a reinforcement post (notshown) between the panels 44 and 48. Similarly, each of the top andbottom right panels 46 and 50 have a set of four apertures 146, 148,respectively, defined adjacent their respective right rear cornerportions. The apertures 146 in panel 46 are aligned with the apertures148 in panel 50. Both sets of apertures 146 and 148 are configured toreceive fasteners for attaching a reinforcement post (not shown) betweenthe panels 46 and 50.

As best shown in FIGS. 9 and 11, the left sidewall member 52 resemblesthe right sidewall member 54—the one being the mirror image of theother, such that a description of the former will generally suffice forthe latter. The sidewall member 52 has an upper edge 160, a lower edge162, a front edge 164 and rear edge 166, and is formed with a curvedportion 168 and a straight portion 170. The left sidewall member 52extends vertically between the top and bottom left panels 44 and 48, andis welded along its upper edge 160 to the lower face 58 of the top leftpanel 44, and along its lower edge 162 to the upper face 174 of thebottom left panel 46. In the case of the right sidewall member 54, itsupper edge 176 is welded to the lower face 178 of top right panel 46 andits lower edge 180 is welded to the upper face 182 of the bottom rightpanel 48.

The curved portion 168 of the left sidewall member 52 extends from thefront edge 164 thereof to terminate at a transition section 184 locatedcloser to the rear edge 166 than the front edge 164. The straightportion 170 of the left sidewall member 52 runs from the transitionsection 184 until the rear edge 166. The left sidewall member 52 isarranged diagonally between the front edges 68 and 124 of the top andbottom left panels 44 and 48 and the rear edges 74 and 192 thereof, withits curved portion 168 positioned opposite the left chipping head 36.Disposed in this fashion, the curved portion 168 defined as a protectivewell 193 for the left chipping head 36. The straight portion 170 of theleft sidewall member 52 flares outwardly away from the curved portion168 and operates to deflect wood chips and chipping debris.

The right sidewall member 54 is similarly formed with a curved portion194 and a straight portion 196, and it extends diagonally between thefront edges 198 and 126 of the top and bottom right panels 46 and 50 andthe rear edges 200 and 202 thereof. The curved portion 194 of the rightsidewall member 54 defines a protective well 195 for the right chippinghead 38. The straight portion 196 of the right sidewall member 52 flaresoutwardly away from the curved portion 150.

The components of the feeder subassembly 24 are now described in greaterdetail. Each feeder roller 28 and 30 is mounted between, and supportedby, portions of the upper linkage mechanism 32 and the lower linkagemechanism 34. As shown in FIGS. 6A and 6B, the upper linkage mechanism32 includes left and right primary linkage arms 210 and 212, left andright secondary linkage arms 214 and 216, and a hydraulic piston 218.The left and right primary linkage arms 210 and 212 connect the left andright feeder rollers 28 and 30, respectively, to the frame 42, while theleft and right secondary linkage arms 214 and 216 tie the left and rightprimary linkage arms 210 and 212, respectively, to the hydraulic piston218.

The left primary linkage arm 210 has an enlarged front end portion 220,a comparatively smaller rear end portion 222 and a tapered intermediateportion 224 joining the front and rear end portions 220 and 222 to eachother. The front end portion 220 is carried forwardly of the front edge68 of the top left panel 44. It has a relatively large aperture (notvisible) formed therein sized to receive the upper portion of the leftfeeder roller 28. Defined in the front end portion 220 at locationssurrounding the relatively large aperture, are bores (not shown) whichare configured to receive therethrough bolts for attaching the leftfeeder roller 28 to the upper linkage mechanism 32.

The rear end portion 222 is also apertured and is configured to fit ontothe short post 92 extending from the cylindrical support member 90. Anut 226 fastened on the threaded upper portion 96 of short post 92retains the rear end portion 222 in place. When the upper linkagemechanism 32 is actuated, the rear end portion 222 can be made to pivotabout the short post 92.

The left secondary linkage arm 214 has a front end 228 pivotallyconnected to the left primary linkage arm adjacent the front end portion220, and a rear end 230 pivotally connected to a short bar 232 attachedto the hydraulic piston 218. The front end 228 of the linkage arm 214 isattached to the top face of the tapered intermediate portion 224.

This arrangement of primary and secondary linkage arms is substantiallyreproduced on the right side of the upper linkage mechanism 32 with theright primary linkage arm 212 and the right secondary linkage arm 216.In like fashion to left primary linkage arm 210, the right primarylinkage arm 212 has an enlarged front end portion 240, a comparativelysmaller rear end portion 242 and a tapered intermediate portion 244joining the front and rear end portions 240 and 242 to each other. Thefront end portion 240 is carried forwardly of the front edge of the topright panel 46. It has an aperture (not visible) formed therein sized toreceive the upper portion of the right feeder roller 30. Defined in thefront end portion 240 at locations surrounding the relatively largeaperture, are bores (not shown) which are configured to receivetherethrough bolts for attaching the right feeder roller 30 to the upperlinkage mechanism 32.

The rear end portion 242 is also apertured and is configured to fit ontothe short post 246 extending from the cylindrical support member 110. Anut 248 fastened on the threaded upper portion of the short post 246retains the rear end portion 242 in place. When the upper linkagemechanism 32 is actuated, the rear end portion 242 is pivotable aboutthe short post 246.

As shown in FIG. 2, by reason of the difference in height between thecylindrical support members 90 and 110, the right primary linkage arm212 is carried higher than the left primary linkage arm 210 relative tothe top left and right panels 44 and 46. This prevents any physicalinterference from occurring between left feeder roller 28 and the rightfeeder roller 30, when the feeder rollers 28 and 30 are moved to theirminimum spacing (see FIG. 6A).

The right secondary linkage arm 216 has a front end (not visible)pivotally connected to the right primary linkage arm 212 adjacent thefront end portion 240, and a rear end 252 pivotally connected to theshort bar 232. The front end 250 of the linkage arm 216 is attached tothe bottom face of the tapered intermediate portion 244. The pivotalconnection between the short bar 232 and the right secondary linkage arm216 lies opposite the pivotal connection between the short bar 232 andthe left secondary linkage arm 214.

The hydraulic piston 218 includes a hydraulic cylinder 260 which isfixed to the frame 42 by a bracket 262 (visible in FIG. 2), and a pistonarm 264 operatively connected to the hydraulic cylinder 260. One end ofthe piston arm 264 is retained within the hydraulic cylinder 260 whilethe opposite end is fixed to the short bar 232. The piston arm 264 ismoveable between a retracted position 266 shown in solid lines in FIG.6B and an extended position 268 shown in FIG. 6A and in dashed lines inFIG. 6B. When the piston arm 264 is in its retracted position 266, theshort bar 232 is disposed closest to the hydraulic cylinder 260 whichcauses the left and right secondary linkage members 214 and 216 to besplayed more widely for maximum spacing between the left feeder roller28 and the right feeder roller 30. When the piston arm 264 is in itsextended position 268, the short bar 232 is disposed furthest from thehydraulic cylinder 260 which causes the left and right secondary linkagemembers 214 and 216 to be brought closer together for minimum spacingbetween the left feeder roller 28 and the right feeder roller 30.

Turning now to the lower linkage mechanism 34 shown in FIG. 8, it can beseen to be generally similar to the upper linkage mechanism 32 in thatit too has left and right primary linkage arms 270 and 272, left andright secondary linkage arms 274 and 276, and a hydraulic piston 278.The left and right primary linkage arms 270 and 272 connect the left andright feeder rollers 28 and 30, respectively, to the frame 42, while theleft and right secondary linkage arms 274 and 276 tie the left and rightprimary linkage arms 270 and 272, respectively, to the hydraulic piston278.

The left primary linkage arm 270 has an enlarged front end portion 280,a comparatively smaller rear end portion 282 and a tapered intermediateportion 284 joining the front and rear end portions 280 and 282 to eachother. The front end portion 280 is carried forwardly of the front edge124 of the bottom left panel 48. It has an aperture (not visible) formedtherein sized to receive a bottom portion of the left feeder roller 28.Defined in the front end portion 280 at locations surrounding therelatively large aperture, are bores (not shown) which are configured toreceive therethrough bolts for attaching the left feeder roller 28 tothe lower linkage mechanism 34.

The rear end portion 282 is also apertured and is configured to fit ontothe short post 286 extending from the cylindrical support member 112. Anut 288 fastened on the threaded upper portion of short post 286 retainsthe rear end portion 282 in place. When the lower linkage mechanism 34is actuated, the rear end portion 282 can be made to pivot about theshort post 286.

The left secondary linkage arm 274 has a front end 300 pivotallyconnected to the left primary linkage arm adjacent the front end portion280, and a rear end 302 pivotally connected to a short bar 304 attachedto the hydraulic piston 278. The front end 300 of the linkage arm 274 isattached to the bottom face of the tapered intermediate portion 284.

This arrangement of primary and secondary linkage arms is substantiallyreproduced on the right side of the lower linkage mechanism 34 with theright primary linkage arm 272 and the right secondary linkage arm 276.In like fashion to left primary linkage arm 270, the right primarylinkage arm 272 has an enlarged front end portion 310, a comparativelysmaller rear end portion 312 and a tapered intermediate portion 314joining the front and rear end portions 310 and 312 to each other. Thefront end portion 310 is carried forwardly of the front edge 126 of thebottom left panel 50. It has an aperture (not visible) formed thereinsized to receive the upper portion of the right feeder roller 30.Defined in the front end portion 310 at locations surrounding therelatively large aperture, are bores (not shown) which are configured toreceive therethrough bolts for attaching the right feeder roller 30 tothe lower linkage mechanism 34.

The rear end portion 312 is also apertured and is configured to fit ontothe short post 316 extending from the cylindrical support member 114. Anut 318 fastened on the threaded upper portion of the short post 316retains the rear end portion 312 in place. When the lower linkagemechanism 34 is actuated, the rear end portion 312 is pivotable aboutthe short post 316.

The right secondary linkage arm 276 has a front end 320 pivotallyconnected to the right primary linkage arm 272 adjacent the front endportion 310, and a rear end 322 pivotally connected to the short bar304. The front end 320 of the linkage arm 276 is attached to the bottomface of the tapered intermediate portion 314. The pivotal connectionbetween the short bar 304 and the right secondary linkage arm 276 liesopposite the pivotal connection between the short bar 304 and the leftsecondary linkage arm 274.

The hydraulic piston 278 includes a hydraulic cylinder 330 which isfixed to the frame 42 by a bracket 331 (visible in FIG. 2), and a pistonarm 332 operatively connected to the hydraulic cylinder 330. One end ofthe piston arm 332 is retained within the hydraulic cylinder 330 whilethe opposite end is fixed to the short bar 304. The piston arm 332 ismoveable between a retracted position (not shown, but generally similarto retracted position 266 of the piston arm 264) and an extendedposition 333 shown in FIG. 8. When the piston arm 332 is in itsretracted position, the short bar 304 is disposed closest to thehydraulic cylinder 330 which causes the left and right secondary linkagemembers 274 and 276 to be splayed more widely for maximum spacingbetween the left feeder roller 28 and the right feeder roller 30. Whenthe piston arm 332 is in its extended position 333, the short bar 304 isdisposed furthest from the hydraulic cylinder 330 which causes the leftand right secondary linkage members 274 and 276 to be brought closertogether for minimum spacing between the left feeder roller 28 and theright feeder roller 30.

It will thus be understood that when actuated the upper and lowerlinkage mechanisms 32 and 34 cooperate with each other to allow the leftand right feeder rollers 28 and 30 to move from their respective firstpositions 334 and 335 (shown in FIG. 6A in solid lines and in FIG. 6B indashed lines) to their respective second positions 336 and 337 (shown inFIG. 6B in solid lines). When the left and right feeder rollers 28 and30 are in their respective first positions 334 and 335, the gap G thatis defined between the outer boundaries of the left and right feederrollers 28 and 30, is at its smallest size. In contrast, when the leftand right feeder rollers 28 and 30 are in their respective secondpositions 334 and 335, the gap G is at largest size. Accordingly, thegap G can be adjusted to accommodate the diameter or width of the branchor other feedstock to be reduced to chips by actuating the upper andlower linkage mechanisms 32 and 34. In this embodiment, the gap G whenat its smallest size measures ⅛ in., sufficient to prevent physicalinterference between the feeder rollers. It will be appreciated that thegap G shown in FIG. 6B, is exaggerated somewhat for the purposes ofillustration. The diameter or width of the branch or feedstock will beless than the gap G when at its largest size.

In this embodiment, the linkage arms and pistons in each mechanism 32and 34 are arranged so that the left feeder roller 28 and the rightfeeder roller 30 are biased in their respective first positions 334 and335 in order to maintain the gap G at its smallest size. In order towiden the gap G (i.e. move the feeder rollers 28 and 30 away from eachother toward their respective second positions 336 and 337), it isnecessary to overcome the biasing force of the upper and lower linkagemechanisms 32 and 34. As explained in greater detail below, this isachieved by applying a force against the left and right feeder rollers28 and 30, which force is generated by a branch or other feedstock as ittravels through the feeder subassembly 24.

It should also be appreciated that the biasing action of the upper andlower linkage mechanisms 32 and 34 tends to enhance the gripping actionof the feeder rollers 28 and 30 and their ability to securely hold thebranch or other feedstock in place while it is conveyed to the chippingsubassembly 26. Moreover, it serves to properly align the branch orother feedstock between the left and right chipping heads 36 and 38.

Turning now to the right feeder roller 30, a description thereof followswith reference to FIGS. 12A to 12C. The right feeder roller 30 includesa roller body 340, a bottom bearing support 342, a bottom shaft 344fixed to the roller body 340 for connecting the bottom bearing support342 to the roller body 340, a drive block 346 and a top shaft 348 fortransmitting the torque generated by the drive block 346 to the rollerbody 340.

The roller body 340 has a hollow cylindrical structure having a top end360, a bottom end 362 and a sidewall 364 extending between the top andbottom ends 360 and 362. In this embodiment, the diameter of the rollerbody is 14 inches. In other embodiments, the diameter of the roller bodycould be sized differently.

The outer surface 366 of the sidewall 364 carries a plurality of spacedapart, conical tips or spikes 368 which are adapted to penetrate thetree branch or feedstock and grip it to allow it to be drawn into thebrush chipper assembly 20. The spikes 368 are arranged along a number ofrows 370. In this embodiment, there are ten (10) rows 370 of spikes 368evenly-spaced about the outer surface 366 (see FIG. 9A). These rows 370alternate between having fifteen (15) or sixteen (16) spikes 368 each.The spikes 368 of any given row 370 are longitudinally offset from thespikes 368 of the next adjacent row for enhanced coverage along theouter surface 366. In other embodiments, the spikes could be laid outalong a different arrangement.

Fixed at the top end 360 and extending into the hollow of the rollerbody 340 is the top splined socket 372. It is welded to a pair of spacedapart annular plates 374 and 376 whose respective outer edges arethemselves welded to the inner surface 378 of the sidewall 364. The topsocket 372 is configured for mating engagement with one end of the topshaft 348.

The bottom end 362 of the roller body 340 is also provided with a socket382 (however, it is not splined), which is held in place by a singleannular plate 384. In like fashion to the outer plates 374 and 376, theouter edge of the annular plate 384 is welded to the inner surface 378of the sidewall 364. In this case, the bottom socket 382 receives thefirst end 386 of the bottom shaft 344, which component is welded inplace.

As shown in FIG. 12B, the bottom shaft 344 includes a second end 388disposed opposite the first end 386, a first shaft portion 390 extendingfrom the first end 386, a second shaft portion 392 extending from thesecond end 388 and a third shaft portion 394 located between the firstand second portions 390 and 392. Adjacent the second end 388, the secondshaft portion 392 has a transverse bore 396 defined therethrough.

The diameter of the first shaft portion 390 remains constant throughoutits length. In contrast, the diameter of the third shaft portion 394tapers along a section of its length in the direction of the second end388. Lastly, the second shaft portion 392 has a diameter that is smallerthan the diameters of the first and third shaft portions 390 and 394.

Referring now FIGS. 12B and 12C, the bottom support bearing 342 includesa hub 400 defined by a sidewall 402. The hub 400 is formed with a tophub portion 404, a bottom hub portion 406 and an intermediate flangeportion 408 disposed between the top and bottom hub portions 404 and406. The top hub portion 404 accommodates a first bearing assembly 410while the bottom hub portion 406 receives a second bearing assembly 412.The top hub portion 404 is partially closed off by a flanged mudextruder 414 provided with a central aperture 416. Surrounding thecentral aperture 416 is a small rebate in which is seated a first O-ringgasket 420. The flanges of the mud extruder 414, on the one hand, and aback-up washer 422, on the other hand, together define a space whichaccommodates a mechanical seal 424. A second O-ring gasket 426 isdisposed between the back-up washer 422 and the sidewall 402 of the tophub portion 404. The flanged mud extruder 414, the first O-ring gasket420, the back-up washer 422 and the mechanical seal 424 are allconfigured to fit snugly around the first shaft portion 390 so as toprevent dust and debris from penetrating into the top hub portion 404and gumming up the first bearing assembly 410.

In this embodiment, the first bearing assembly 410 is a cup and conebearing. It includes a cup or outer ring 430 and a cone or inner ring432 in abutting engagement with the outer ring 430. The inner ring 432is sized to receive a section of the third shaft portion 394. The outerring 430 sits between the inner surface of the hub sidewall 402 and theinner ring 432.

The second bearing assembly 412 is similar to the first bearing assembly410 in that it too is a cup and cone bearing having an outer ring 434and inner ring 436. However, the outer and inner rings 434 and 436 aresized smaller than the outer and inner rings 430 and 432 because thesecond bearing assembly 412 accommodates a section of the third shaftportion 394 that has a smaller diameter than that of the shaft sectionreceived in the first bearing assembly 410. Also, the outer and innerrings 434 and 436 are disposed in a mirror image arrangement (along anotional horizontal line not shown running through the intermediateflange portion 408) to the outer and inner rings 430 and 432 of thefirst bearing assembly 410.

A castle nut 440 is provided for retaining the second bearing assembly412 in place within the bottom hub portion 406. The castle nut 406 issized to fit on the second shaft portion 392 and in conjunction with acotter pin 408, fixedly retain the shaft 344. A hub cap 442 is attachedto the hub 400 to close off the bottom hub portion 406. Disposed betweenthe hub cap 442 and the hub 400 is an O-ring gasket 444. A greasefitting 446 is incorporated into the hub cap 442 to lubricate the secondbearing assembly 412.

The intermediate flange portion 408 is formed with a thick collar 448from which a six-lobed, star-shaped, projection 450 stands proud. Eachlobe 452 of the projection 450 has an aperture 454 defined therein thatextends right through the collar 448. Each aperture 454 is configured toreceive a bolt 456 therethrough for securing the hub 400 to the rightprimary linkage arm 272 of the lower linkage mechanism 34. When theright feeder roller 30 is operatively connected to the lower flangemechanism 32, the bottom hub portion 406 is received through theaperture defined in front end portion 310 of the lower right primarylinkage arm 272, and the collar 448 rests upon and is supported by thefront end portion 310.

As shown in FIGS. 1 and 12A, the top shaft 348 has a cylindrical shaftportion 460 that terminates with a mounting plate 462. The end 464 ofthe shaft portion 460 opposite the mounting plate 462 is splined formating engagement with the top socket 372. The mounting plate 462 has aplurality of bores (not visible) defined therein which are alignablewith corresponding bores (not visible) defined in the mounting plate 466of a drive shaft 468 (which forms part of the drive block 346) to allowbolts to be inserted therethrough to securely fasten the drive shaft 468to the top shaft 348.

The drive block 346 includes a housing 470 having top and bottomportions 472 and 474 that meet at an intermediate flanged section 476, ahydraulic motor 478 accommodated within the housing 470, and a driveshaft 468 operatively connected to the motor 478. The intermediateflange section 476 of the housing 470 has a plurality of bores (notvisible) which are alignable with the bores defined in the right primarylinkage arm 212 of the upper linkage mechanism 32, and which areconfigured to receive bolts 479 therethrough to fixedly secure the driveblock 346 to the upper linkage mechanism 32. When the right feederroller 30 is operatively connected to the upper flange mechanism 32, thebottom housing portion 474 is received through the aperture defined infront end portion 240 of the upper right primary linkage arm 212, andthe flanged section 476 rests upon and is supported by the front endportion 240. It will thus be appreciated the right feeder roller 30 isheld in place by the upper right primary linkage arm 212 of the upperlinkage mechanism 32 and the lower right primary linkage arm 272 of thelower linkage mechanism 34, with the drive block 346 being substantiallysupported by the upper right primary linkage arm 212.

The mounting plate 466 of the drive shaft 468 protrudes from the bottomhousing portion 472. It is of a size to match the mounting plate 466 ofthe top shaft 348. When the motor 478 is actuated, the drive shaft 468is urged to rotate and, by reason of the fixed connection between themounting plates 466 and 462, is able to transmit torque to the top shaft348 (and ultimately, to the roller body 340).

While it is preferred that the motor 476 be hydraulically-powered, itwill be appreciated that this need not be the case in every application.In other embodiments, other motors may be used to similar advantage, forinstance, pneumatically-powered motors or gas-powered motors.

Referring to FIGS. 1, 2 and 4, it can be seen that the left feederroller 28 is generally similar to the right feeder roller 30 in that ittoo includes a roller body 490, a bottom bearing support 492, a bottomshaft (not visible) fixed to the roller body 490 for connecting thebottom bearing support 492 to the roller body 490, a drive block 496 anda top shaft 498 for transmitting the torque generated by the drive block496 to the roller body 490. The structure of the components 490, 492,496 and 498 of the left feeder roller 28, their function and theirarrangement relative to each other, are generally similar to those ofcorresponding components 340, 342, 346 and 348 of the right feederroller 30, such the description of the former will generally suffice forthe latter, except that in the case of the top shaft 498, itscylindrical shaft portion 500 is shorter than the cylindrical shaftportion 462 of the top shaft 348. In like fashion to the right feederroller 30, the left feeder roller 28 is held in place by the upper leftprimary linkage arm 210 of the upper linkage mechanism 32 and the lowerleft primary linkage arm 270 of the lower linkage mechanism 34, with thedrive block 496 being substantially supported by the upper left primarylinkage arm 210.

With reference to FIGS. 3, 7A, 7B, 13A to 13C, the components of thechipping subassembly 26 are now described in greater detail. Eachchipping head 36 and 38 is mounted for rotation within the housing 22.The left chipping head 36 is positioned within the well 193 and extendssubstantially between the top left panel 44 and the bottom left panel48. In the case of right chipping head 38, it is disposed within thewell 195 and extends substantially between the top right panel 46 andthe bottom right panel 50. As explained in greater detail below, theupper portion of each head 36, 38 protrudes from the top of the housing22 to be operatively connected to the drive assembly 40.

The left and right chipping heads 36 and 38 are similar to each other inall material respects such that a description of one (i.e. the rightchipping head 38) will suffice for the other (i.e. the left chippinghead 36). However, where appropriate, specific reference may be made toone or more components of the left chipping head 36, it being understoodthat such components resemble corresponding components of the rightchipping head 38 described below such that no further description isrequired. In such cases, the components of the left chipping head 36shall be identified with same reference numerals as used for likecomponents of the right chipping head 38, except that all referencenumerals designating components of the left chipping head 36 shall alsoinclude the suffix “a”.

FIGS. 13A to 13C show the right chipping head 38 and components thereof.The right chipping head 38 includes a tubular support body 520, andupper and lower coupling assemblies 522 and 524 housed substantiallywithin the hollow 526 defined in the support body 520. The support body520 has an upper end 528, a lower end 530 and an intermediate portion532 extending between the upper and lower ends 528 and 530. In thisembodiment, the support body 520 is cylindrical; its circularcross-section defined by a circumferential wall 534 having an outersurface 536 and an inner surface 538. As explained in greater detailbelow, the outer surface 536 carries a plurality of protective collars539 mounted concentrically to the support body 520 at spaced intervalsalong the intermediate portion 532, and a plurality of cutting toothassemblies 540—each cutting tooth assembly 540 being nestled between anadjacent pair of collars 539.

The thickness of the circumferential wall 534 is not constant throughoutthe length of the support body 530. More specifically, thecircumferential wall 534 is thinner at the regions 542 and 544 of thesupport body 520 (which regions extend inwardly from the upper and lowerends 528 and 530 a short distance) than at the mid-length of the supportbody 210. In the regions 542 and 544 the hollow 526 has a greatercross-sectional area to accommodate the upper and lower couplingassemblies 522 and 524. Defined by the increased thickness of thecircumferential wall 534 beyond the regions 542 and 544, arecircumferentially extending shoulders 546 and 548 upon which portions ofthe upper and lower coupling assemblies 522 and 524 will abut. As shownin FIG. 13A, the upper coupling assembly 522 is adapted to fit withinthe hollow 526 in region 542, while the lower coupling assembly 524 isdesigned to fit in the hollow 526 in region 544.

Referring now to FIGS. 13B and 13C, there is shown the upper couplingassembly 522 which includes a mounting plate 550 for fixing to thesupport body 520, a coupling member 552, a flanged annular member 554, afirst annular sealing gasket 556, a first retaining ring 558, a bearingassembly 560, a second retaining ring 562, a mounting ring 564, abearing support member 566 and a second annular sealing gasket 568.

The mounting plate 550 has an annular body 570 with a central aperture572, a first face 574 and a second opposed face 576. The first face 574is joined to the second face 576 by a sidewall 578 formed by a narrowcircumferential band 580 and a tapering sidewall portion 582. Whenmounting the plate 550 to the support body 520, the peripheral edge ofthe first face 574 is urged to abut the circumferential shoulder 546 ofthe support body 520. The narrow band 580 is brought to bear against theinner surface 538 of the support body 520 and the mounting plate 550 iswelded to the support body 520 about its tapering sidewall portion 582.Defined in the mounting plate 550 is a plurality of bores 584 sized toaccommodate fasteners in the nature of threaded fasteners 586.

The coupling member 552 includes a disc-shaped portion 590 having afirst face 592, a second face 594 and a plurality of circumferentiallyspaced bores 596 defined therein extending between the first and secondfaces 592 and 594. Standing proud of the first face 592 is a puck-likeprojection 598 that is sized for clearance fit with the central aperture572 formed in the mounting plate 550. During fabrication, the first face592 of the coupling member 552 is brought to bear against the secondface 576 of the mounting plate 550 with the puck-like projection 598locating in the central aperture 572. Thereafter, the coupling member552 is fastened to the mounting plate 550 by inserting the fasteners 586into the aligned the bores 584 and 596 and tightening them. The couplingmember 552 further includes a cylindrical portion 600 that extendsoutwardly from the second face 594. The cylindrical portion 600 has akeying projection 602 for mating engagement with a portion of the driveassembly 40.

The flanged annular member 554 is defined at least partially by asidewall 604. A first circumferential lip or flange 606 extendsoutwardly from the edge of the sidewall 604. The first flange 606 hasdefined therein a plurality of circumferentially spaced apertures 608.Radially bounding the central aperture 610 formed in the flanged member554 is a second, inwardly projecting flange 612. The second flange 612forms a seat for the first sealing gasket 556. When the upper couplingassembly 522 is assembled, the flanged annular member 554 surrounds thecylindrical portion 600 and the first gasket 556 tends to form a sealbetween the flanged annular member 554 and the cylindrical portion 600to prevent dust or debris from fouling the lubricant that coats thebearings (not shown) of the bearing assembly 560.

The second gasket 568 disposed at the opposite end of the bearingassembly 560 and mounted between the bearing assembly 560 and aninwardly extending flange 644 of the bearing support member 566, servesa similar sealing function. Again, while it is generally preferred thatgaskets 556 and 568 be employed, in alternative embodiments thesegaskets may be omitted.

The bearing assembly 560 includes a generally annular body 620 having acentral aperture 622 defined therethrough. Within the hollow 624 of thebearing support member 566, the annular body 620 is securely retained atone end by the second retaining ring 562 mounted in surrounding relationwith the cylindrical portion 600 and at the opposite end by the firstretaining ring 558 which engages the inner surface of the sidewall 628of the bearing support assembly 558. Housed within the annular body 620is a plurality of bearings (not shown) disposed circumferentially aboutthe central aperture 622. When the upper coupling assembly 522 isassembled, the bearing assembly 560 surrounds the cylindrical portion620 and allows free rotation of the coupling member 552 relative to thebearing support member 566. The bearing assembly 560 uses rollerbearings.

The bearing support member 566 has a generally tubular body 630 having afirst end 632, a second end 634 and sidewall 628 extending between thefirst and second ends 632 and 634. Extending outwardly from the edge ofthe sidewall 628 at the first end 632 is a first circumferential lip orflange 636. The first flange 636 has defined therein a plurality ofcircumferentially spaced apertures 638 which are alignable withapertures 640 defined in the mounting ring 564 and apertures 642 formedin the top right panel 46. At its first end 632, the tubular body 630also has second, inwardly projecting flange 644 that radially bounds thehollow 624 in the tubular body 630. When the upper coupling assembly 522is assembled, the second gasket 568 sits on the cylindrical portion 600and abuts the inner face of the second flange 644. A plurality oflongitudinal bores 646 drilled into the sidewall 628 at the second end634 are alignable with the apertures 608 defined in the first flange 606of the flanged annular member 554. During fabrication, threadedfasteners 648 are inserted through bores 646 and 608 and tightened toattach the bearing support member 558 to the flanged annular member 554.

Turning now to the lower coupling assembly 524, it is similar in allmaterial respects to the upper coupling assembly 522 in that the formerincludes the same components as the latter, arranged in the same manner,with the exception that the lower coupling assembly 524 includes oneadditional component described below. In common with the upper couplingassembly 522, the lower coupling assembly 524 includes a mounting plate660 for fixing to the support body 520, a coupling member 662, a flangedannular member 664, a first annular sealing gasket (not visible), afirst retaining ring (not visible), a bearing assembly (not visible), asecond retaining ring (not visible), a mounting ring 666, a bearingsupport member 668 and a second annular sealing gasket (not visible).However, the lower coupling assembly 524 further includes an annular endplate 670 for mounting to the lower end of bearing support member 558 toclose off the hollow therein. But for the annular end plate 670, theupper and lower coupling assemblies 522 and 524 could be said to be amirror image one of the other disposed at opposite regions 542 and 544of the support body 520. Components 660, 662, 664, 666, 668, 670 arevisible in FIG. 13A.

FIGS. 3, 9A, 9B and 10 show the arrangement of collars 539 and cuttingtooth assemblies 540 along the support body 520. This arrangement willbe known to those skilled in the art as a substantially similararrangement is described in U.S. Pat. No. 7,980,278 of Labbe et al.incorporated herein by reference. Accordingly, for the purposes of thisdescription, it will suffice to describe this arrangement only verybroadly.

Each collar 539 has a substantially penannular structure defined by arelatively flat, circumferentially extending, sidewall 700 formed with acutout 702 (see FIG. 9B). Each collar 539 is radially mounted to thesupport body 520 with its inner sidewall edge welded to the outersurface 536 of the support body 520. The spacing between adjacentcollars 539 is sized to correspond generally to the width of the cuttingtooth assembly 540. Each collar 539 is radially offset from its adjacentcollar 539 such that the cutouts 700 of adjacent collars are staggeredrelative to each other. In this embodiment, a station 704 is definedbetween each cutout 700 formed in a given collar 539 and that portion ofeach sidewall 700 of an adjacent collar 539 that is disposed oppositesuch cutout 700. Each station 704 is sized to accommodate therein aportion of a cutting tooth assembly 540.

The cutting tooth assembly 540 includes a cutting tooth 710 and amounting assembly 712 for securely fixing the cutting tooth 540 within arespective station 704. The cutting tooth 710 has a base portion 714 anda cutting portion 716 which extends from the base portion 714 in agenerally canted fashion. The cutting tooth portion 716 has a tapering,wedge-like, profile that terminates in a cutting edge 718. When thecutting tooth 710 is mounted within the station 704, the cutting edge718 extends beyond the outermost edges of sidewalls 700 of adjacentcollars 539. During actuation of the right chipping head 38, the cuttingedge 718 tends to be the first element of the cutting tooth 540 to makecontact with the feedstock.

The mounting assembly 706 includes a mounting block 730 disposedforwardly of the cutting tooth 540, a mounting plate 732 disposedrearwardly of the cutting tooth 590, a fastener in the nature of a nut734 and bolt 736 (visible in FIG. 3) for securing the cutting tooth 590to the mounting block 730 and the mounting plate 732, an abutment plate738 supported on the outer edges of adjacent collars 539 and bearingagainst a portion of the cutting tooth 710, and a C-shaped retainingmember 740.

Having described the various components of the chipping heads 36 and 38,the arrangement of these chipping heads within the frame 42 is nowexplained in greater detail with reference to FIGS. 3, 4 and 5. Duringfabrication of the brush chipper assembly 20, before the left and rightside of the frame 42 are fastened to each other, the right chipping head38 is positioned between the top and bottom right panels 46 and 50within the well 193, with its longitudinal axis generally aligned withthe rebates 82 and 86 defined in the panels 46 and 50. At the upper endof the right chipping head 38, the mounting ring 564 abuts the top rightpanel 46 and is sandwiched between the latter and the bearing supportmember 566 (see FIGS. 3 and 4). Similarly, at the lower end of the rightchipping head 38, the mounting ring 666 abuts the bottom right panel 50and is sandwiched between the latter and the bearing support member 668.Thereafter, the upper and lower ends of the right chipping head 38 arefastened to the frame 42. More specifically, at the upper end of theright chipping head 38, fasteners (not visible) are inserted through thealigned apertures 638, 640 and 642 of the bearing support member 566,the mounting ring 564 and the top right panel 46, and secured. In likefashion, at the lower end of the right chipping head 38, fasteners (notvisible) are inserted through the aligned apertures of the bearingsupport member 668, the mounting ring 666 and the bottom panel 50, andsecured.

The left chipping head 36 is similarly arranged within the frame 42between the top and bottom left panels 44 and 48 within the well 195,with its longitudinal axis generally aligned with the rebates 80 and 84defined in the panels 44 and 48, except that, as best seen in FIGS. 9and 10, the left chipping head 36 is oriented so as to be the mirrorimage of the right chipping head 38. Arranging the left chipping head 36in this manner ensures that cutting teeth 540 a carried on the supportbody 520 a are properly oriented so that their respective cutting edges718 a contact the feedstock first when the left chipping head 36 isrotated in the clockwise direction.

At the upper end of the left chipping head 36, the mounting ring 564 aabuts the top left panel 44 and is sandwiched between the latter and thebearing support member 566 a (see FIGS. 3 and 5). Similarly, at thelower end of the left chipping end 36, the mounting ring 666 a abuts thebottom left panel 48 and is sandwiched between the latter and thebearing support member 668 a. Thereafter, the upper and lower ends ofthe left chipping head 36 are fastened to the frame 42 in like fashionto the manner of the upper and lower ends of the right chipping head 38.

In this embodiment, the spacing S between the chipping heads 36 and 38as measured between the outermost margin or envelope of each chippinghead is ⅛ in. a space sufficient to prevent physical interferencebetween the chipping heads. The spacing S, shown in FIG. 9, isexaggerated somewhat for the purposes of illustration.

With reference to FIGS. 3, 7A and 7B, the drive assembly 40 which drivesrotation of the left and right chipping heads 36 and 38, is nowdescribed in greater detail. In this embodiment, the drive assembly 40takes the form of a belt drive 760 operatively connected to a hydraulicmotor 762. The belt drive 760 includes a notched belt 764, a drivingpulley 766 connected to the hydraulic motor 762, a right driven pulley768 attached to the right chipper head 38 and a left driven pulley 770attached to the left chipper head 36. The inner surface of the notchedbelt 764 is provided with notches for tracked engagement with teeth (notshown) carried on the pulleys 766, 768 and 770.

The driving pulley 766 has a hub portion 774 and a flanged rim portion776 surrounding the hub portion 774. The rim portion 776 is fixed forrotation with the hub portion 774. The hub portion 774 has a centralaperture 778 which is sized to receive the drive shaft 780 of thehydraulic motor 762. The rim portion 776 has teeth (not shown) whichengage the notches in the notched belt 764.

The right and left driven pulleys 768 and 770 are sized relativelysmaller than the driven pulley 766. The right driven pulley 768 issimilarly formed with a hub portion 782 and a flanged rim portion 784surrounding the hub portion 782. The rim portion 784 is fixed forrotation with the hub portion 782. The hub portion 782 has a centralaperture 786 which opens onto an elongate groove 788. The centralaperture 776 receives the cylindrical portion 600 of the coupling member552 with the keying projection 602 fitting into the groove 788 to fixthe coupling member 552 for rotation with the hub portion 782.

The left driven pulley 770 is disposed between the driving pulley 766and the right driven pulley 768. The left driven pulley 770 resemblesthe right driven pulley 768 in that it too has a hub portion 790 and aflanged rim portion 792 surrounding the hub portion 790. The rim portion792 is fixed for rotation with the hub portion 790. The hub portion 790has a central aperture 794 which opens onto an elongate groove 796. Thecentral aperture 794 receives the cylindrical portion 600 a of thecoupling member 552 a with the keying projection 602 a fitting into thegroove 796 to fix the coupling member 552 a for rotation with the hubportion 790.

The notched belt 764 is operatively connected to the driving pulley 766,the left driven pulley 770 and the right driven pulley 768. The notchedbelt 764 is laid out between the driving pulley 766 and the left drivenpulley 770 in a cross-belt arrangement such that the left driven pulley770 is urged to rotate in a direction opposite to that of the drivingpulley 766. In contrast, the notched belt 764 is laid out between thedriving pulley 766 and the right driven pulley 768 in an open-beltarrangement such that the right driven pulley 768 is urged to rotate inthe same direction as the driving pulley 766. It will thus beappreciated that by reason of this configuration, when the hydraulicmotor 762 is actuated the right chipping head 38 is urged to rotate in acounter-clockwise direction and the left chipping head 36 is rotated inthe clockwise direction.

The hydraulic motor 762 is mounted to the underside of the top leftpanel 44, with its drive shaft 780 projecting through the circularaperture 132 defined in the panel 44 for connection to the drivingpulley 766.

While in the present embodiment, the left and right chipping heads 36and 38 are driven by a single motor and a drive belt arrangement, in analternative embodiment, the chipping subassembly could be provided withtwo motors—one motor for directly driving each chipping head.

The brush chipper assembly 20 further includes a controller (not shown)which is operable to govern the operation of the drive assembly 40 andthe drive blocks 346 and 496. More specifically, the controller canregulate the flow of hydraulic fluid to motors 462, 476 and 476 a toadjust the speed at which the chipping heads 36 and 38 and the feederrollers 26 and 28 rotate.

A description of an exemplary mode of operation of the brush chipperassembly 20 now follows. As a first step, the hydraulic motor 762 of thedrive assembly 40 is actuated causing the torque from its drive shaft780 to be transmitted to the notched belt 764. As the notched belt 764travels along the drive path defined by the driving pulley 770 and theright and left driven pulleys 768 and 770, it urges the right chippinghead 38 to rotate in a clockwise direction and the left chipping head 36to rotate in a counter-clockwise direction. The left and right chippingheads 36 and 38 are both rotated at the same, or substantially the same,speeds. Preferably, the rotational speed of the chipping heads 36 and 38ranges between 2000 and 3500 RPMs (revolutions per minute).

Next, the hydraulic motor 476 of the right feeder roller 30 and thehydraulic motor 476 a of the left feeder rollers 28 are actuated causingthe right feeder roller 30 to rotate in a clockwise direction and theleft feeder roller 28 to rotate in a clockwise direction. The left andright feeder rollers 28 and 30 are both rotated at the same, orsubstantially the same speeds, by regulating the flow of hydraulic fluidto the hydraulic motors 476 and 476 a. The controller adjusts therotational speed of the feeder rollers 28 and 30 to ensure that thespeed at which the feedstock is fed into the brush chipper assembly 20is matched with the chipping capacity of the chipping heads 36 and 38for optimized chipping efficiency.

With the feeder and chipping subassemblies 24 and 26 actuated, the brushchipper assembly 20 is ready to receive a branch or other feedstock(designated with reference numeral 810 in FIG. 10) to be reduced tochips 812. The operator of the brush chipper assembly 20 introduces orfeeds the branch 810 into the feeder subassembly 24. Preferably, thebranch 810 is of a size no greater than the diameter of the rollerbodies of the left and right chipping heads 36 and 38.

As the branch 810 approaches the gap G, its outer surface 814 is engaged(i.e. pierced or penetrated) by the spikes 368 on the right roller body340 and the spikes 816 on the left roller body 490. The spikes 268 and814 tightly grip the branch 810 and the counter-rotation of the feederrollers 28 and 30 draws the branch 810 rearward toward the chippingsubassembly 26.

Because the left and right feeder rollers 28 and 30 are biased in theirrespective first positions 334 and 335 and the diameter or width of thebranch 810 is sized larger than the gap G, the branch 810 cannot passthrough the gap G unless the biasing force of the upper and lowerlinkage mechanisms 32 and 34 is overcome. The counter-rotation of thefeeder rollers 36 and 38 generates a propulsive force which is greaterthan the biasing force of the linkage mechanisms 32 and 34 causing thepiston arm 264 of hydraulic piston 218 to move from its extendedposition 268 to its retracted position 266, and the piston arm 332 ofhydraulic piston 278 to move from its extended position 333 to itsretracted position. As the leading end of the branch 810 advancesbetween the feeder rollers 36 and 38 it acts as a wedge between them,widening the gap G.

The propulsive force of the feeder rollers 36 and 38 conveys the branch810 to the chipping subassembly 26 where the branch 810 is acted upon bythe plurality of cutting teeth 540 a and 540 of the left and rightchipping heads 36 and 38. As the left chipping head 36 rotates in acounter-clockwise direction, the cutting edges 718 a of the cuttingteeth 540 a are brought to bear against the leading end of the branch810. Similarly, the clockwise rotation of the right chipping head 38causes the cutting edges 718 of the cutting teeth 540 to come intocontact with the leading end of the branch 810.

Contrary to conventional chippers where cutting edges chip the branchworking from the outside toward the inside, the cutting edges 718 a and718 operate like mini-log splitters to split the inner portion of thebranch 810 to produce chips 812. In essence, the cutting edges 718 a and718 chip the branch 810 working from the inside toward the outside. Whenthe cutting edges 718 a and 718 impact the branch 810, the cutting teeth540 a and 540 with their wedge-like profiles split the inner portion ofthe branch 810 as the branch 810 is urged deeper into the chippingsubassembly 26 by the propulsive force of the feeder rollers 36 and 38.The horizontal component of the force generated by the impact of thecutting edges 718 a and 718 on the branch 810, acts in a directionopposite to the direction of the propulsive force of the feeder rollers36 and 38 (i.e. the direction of travel of the branch 810). As a result,this manner of chipping tends to be very effective. The branch 810 isbroken down into large fragments which are then further reduced intosmaller-sized chips.

With two counter-rotating chipping rollers 36 and 38, the brush chipperassembly 20 is able to expose the branch 810 to twice the effectivecutting action of that of a single chipping roller of the same diameter.To achieve the same cutting action with a single chipping roller itwould be necessary to use a chipping roller having a much largerdiameter. Such a chipping roller would tend to be much heavier andtherefore require a more powerful motor to drive it and more robustframe and bearing arrangement to accommodate its rotation. Moreover, itis likely that because of its weight and safety considerations relatedthereto, such a heavier chipping roller would not be driven as fast astwo smaller and lighter chipping rollers, thus resulting incomparatively less frequent contact between the cutting teeth and thebranch, and comparatively lower chipping efficiency.

The chips 812 thus produced are evacuated from the interior of thehousing 22 by the rotational movement of the chipping heads 36 and 38.The chips 812 may follow one of several paths out the rear of thehousing 22. One path has the chips 812 circulating in the well 193between the curved portion 168 of the left sidewall member 52 and theleft chipping head 36. Another path has the chips 812 travelling in thewell 195 between the curved portion 194 of the right sidewall member 54and the right chipping head 38.

In the embodiments described above and shown in FIGS. 1 to 5, the feederrollers 28 and 30 and the chipping heads 36 and 38, are all verticallyoriented. This need not be the case in every application. In otherembodiments, the chipper assembly could be configured with its feederrollers and chipping heads all oriented horizontally.

Although the foregoing description and accompanying drawings relate tospecific preferred embodiments of the present invention as presentlycontemplated by the inventor, it will be understood that variouschanges, modifications and adaptations, may be made without departingfrom the spirit of the invention.

What is claimed is:
 1. A brush chipper assembly comprising: a housing; afeeder subassembly connected to the housing; the feeder subassemblyincluding opposed, first and second feeder rollers; when the feedersubassembly is actuated, the first feeder roller is operable to rotatein a first direction and the second feeder roller is operable to rotatein a second direction so as to draw the brush to be chipped into thehousing; the first direction being opposite to the second direction; achipping subassembly substantially contained within the housing behindthe feeder subassembly; the chipping subassembly including first andsecond, opposed chipping heads and a drive assembly for driving rotationof the first and second chipping heads; each chipping head carrying aplurality of cutting teeth for chipping the brush fed into the brushchipper assembly; when the chipping subassembly is actuated, the firstchipping head is operable to rotate in a third direction and the secondchipping head is operable to rotate in a fourth direction; the thirddirection being opposite to the fourth direction and the firstdirection; the fourth direction being opposite to the second direction.